What is "swscan.apple.com" ?

Hello,

I'm currently using a Intel-based Macbook Air running macOS 11.3.1 .

The first time I checked for the macOS 11.4 update in System Preferences's Software Update panel, I saw the message "Updates for this Mac are managed by 'swscan.apple.com' " displayed on the bottom left corner of the Software Update panel. When I clicked "Details...", I was asked to choose if I would like to restore to default.

I have never installed any pre-release versions of macOS on this Macbook. This situation had never happened to me before macOS Big Sur 11.4 was officially released. Could anyone kindly let me know what the message means? Thank you!